Monolithically integrated twin ring diode lasers for rotation sensing applications

Design, fabrication, and characterization of monolithically integrated ring diode lasers (RDLs) with relatively large size are reported. Fully functional optoelectronic integrated circuits containing integrated unidirectional RDLs, photodetectors, and coupling waveguides are demonstrated. Multiple switching of lasing direction is observed in RDL with quantum-well active regions, and an S-section or spiral absorbers are used to suppress directional switching and to obtain a more stable unidirectional operation. Unidirectionality of the RDL operation is greatly improved in lasers with quantum-dot active regions.